Fix issue where revealed widget children do not receive paint event.

When a child of a widget is spontaneously revealed due to a call to
the parent 'resize' method, the child will not receive a paint event
if it has the WA_StaticContents and WA_OpaquePaintEvent flags set.

This is caused by the backing store being pre-emptively resized by the
call to setGeometry_sys, which causes QWidgetBackingStore::sync to skip
the block which handles the static contents.

There doesn't appear to be any reason to preemptively resize the backing
store, since it is always resized as-needed during the the 'sync' method.
This change-set removes the code which preemptively resizes the backing
store.

Task-number: QTBUG-35282
Change-Id: Ie9942854ca5322dfe0f98ed8100810161576be80
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 21e0286086..dd3d041f56 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -441,6 +441,8 @@ private slots:
     void mouseDoubleClickBubbling_QTBUG29680();
     void largerThanScreen_QTBUG30142();
 
+    void resizeStaticContentsChildWidget_QTBUG35282();
+
 private:
     bool ensureScreenSize(int width, int height);
     QWidget *testWidget;
@@ -10220,5 +10222,26 @@ void tst_QWidget::largerThanScreen_QTBUG30142()
     QVERIFY(widget2.frameGeometry().x() >= 0);
 }
 
+void tst_QWidget::resizeStaticContentsChildWidget_QTBUG35282()
+{
+    QWidget widget;
+    widget.resize(200,200);
+
+    UpdateWidget childWidget(&widget);
+    childWidget.setAttribute(Qt::WA_StaticContents);
+    childWidget.setAttribute(Qt::WA_OpaquePaintEvent);
+    childWidget.setGeometry(250, 250, 500, 500);
+
+    widget.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&widget));
+    QVERIFY(childWidget.numPaintEvents == 0);
+    childWidget.reset();
+
+    widget.resize(1000,1000);
+    QVERIFY(QTest::qWaitForWindowExposed(&widget));
+    QGuiApplication::sync();
+    QVERIFY(childWidget.numPaintEvents >= 1);
+}
+
 QTEST_MAIN(tst_QWidget)
 #include "tst_qwidget.moc"